Properties of the Number 7820

Seven Thousand Eight Hundred Twenty

Basics

Value: 7819 → 7820 → 7821

Parity: even

Prime: No

Previous Prime: 7817

Next Prime: 7823

Digit Sum: 17

Digital Root: 8

Palindrome: No

Factorization: 2 ² × 5 × 17 × 23

Divisors: 1, 2, 4, 5, 10, 17, 20, 23, 34, 46

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2730 Try Today's Challenge

Representations

Binary: 1111010001100

Octal: 17214

Duodecimal: 4638

Hexadecimal: 1e8c

Square: 61152400

Square Root: 88.43076387773658

Classification

Fibonacci: No

Bell Number: No

Factorial Number: No

Regular Number: No

Perfect Number: No

Special

Kaprekar Constant: No

Munchausen Constant: No

Armstrong Number: No

Kaprekar Number: No

Catalan Number: No

Vampire Number: No

Taxicab Number: No

Super Prime: No

Friedman Number: No

Fermat Number: No

Cullen Number: No

OEIS Sequences

4-dimensional pyramidal numbers: a(n) = (3·n+1)*binomial(n+2, 3)/4. Also Stirling2(n+2, n). A1296

a(n) = solution to the postage stamp problem with 7 denominations and n stamps. A53346

Number of strict integer partitions of n with at least one neighborless part. A356607

T(n,k)=Number of nXk 0..5 arrays with every nonzero element less than or equal to some horizontal or vertical neighbor. A203057

Numbers k such that 1 + 3·10^k + 100^k is prime. A171376

Denominators of fractions with the same position in A020652/A038567 and A182972/A182973. A182976

Numbers that are the sum of five third powers in exactly eight ways. A345184

Riordan array (1/(1-xc(2x)),xc(2x)/(1-xc(2x))), c(x) the g.f. of A000108. A110506

An invertible triangle of ratios of triple factorials. A112333

Least common multiple of reversals of divisors of n in decimal representation. A188649